1. Field of the Invention
This invention relates broadly to endotracheal tubes. More particularly, it concerns endotracheal tubes that have improved connector units fitted to their proximal ends by which the endo tubes may be attached to a breathing circuit or like fluid flow machines in a manner that mitigates interference with operations being performed on patients intubated with the endo tubes.
2. Description of the Prior Art
Conventional endotracheal tubes are arcuate in shape (bowed) intubation of patients, for example, see U.S. Pat. Nos. 3,599,642 and 3,848,605. When such tubes have been properly positioned in the trachea, they assume the anatomical shape.
An intubation can be done via the oral or the nasal route with the choice of route being often determined by the procedure applied to the patient. Hence, endotracheal tube are manufactured with extra length so that anatomical differences between patients will be accommodated and also so the tubes can be used nasally or orally since the nasal route requires a longer tube than the oral route. Quite often, the anesthetist will size the tube to the patient by cutting off approximately 30% at the proximal end . . . Thus, in oral intubations, the extra length of the tracheal tube will extend beyond the mouth. Such excess length can be a concern because there is a possibility that the tube could be accidently bent over and kinked thereby creating a blockage.
Conventionally the endotracheal tubes have a 15.0 mm coupler which adapts them to the breathing circuit which, in turn, connects to a ventilator. The breathing circuit usually consists of two thin wall, corrugated, flexible tubes, usually about 1.25" in diameter. Both are brought to the tracheal tube and joined to it through the 15.0 mm coupler. The position of this rather bulky breathing circuit can create complications for the surgeon operating on the intubated patient.
Some pre-shaped tubes have been manufactured for nasal and oral use. Such tubes for oral use have a bend at the point where the tube exits from the patient's mouth to make the tube extend down across the patient's chin.
Alternatively, such tubes for nasal use have a bend where the tube exits from the patient's nose to take the tube back over the forehead of the patient (see U.S. Pat. No. 3,964,488). However, tubes of these types have the disadvantage of being limited to the two stated directions and the permanent bends in the tubes limit the anesthetists' ability to position the distal end in the trachea. Thus, if the distance from the bend to the distal end tip is too long, as might be the case with a short necked patient, the anesthetist can pull the tube back, but this extends the bend away from the patient. This means that the bend is in the wrong place for that particular patient. It is possible that the opposite can happen with long-necked patients leaving the balloon cuff of the tracheal tube crowding the patient's vocal cords. Another disadvantage is that hospitals using such preformed tubes must stock both the oral and nasal type along with the more widely used bowed tubes.
Other ways of getting the proximal end of tracheal tubes and connection elements out of the way of a surgeon have been developed. For example, one approach is to provide a metal coupler shaped to bend down over the chin of a patient when attached to the proximal end of a conventional tracheal tube (see U.S. Pat. No. 2,912,982). Also, central portions of tracheal tubes have been provided with corrugations to create sections therein that can be bent without kinking the tubes thus enabling the tubes to be shaped to bend in a desired direction (see U.S. Pat. Nos. 4,050,466 and 4,275,724). Yet another approach has been to provide adapters having a flexible, bellows like portion to be attached to the proximal end of tracheal tubes to provide a bendable connection betw the tracheal tubes and anesthesia machines (see U.S. Pat. No. 3,388,705).
The present invention provide a further solution to the problems experienced in the use of endotracheal tubes as discussed above that permits hospitals to stock only the commonly used type of bowed tracheal tubes. At the same time, the anesthetist can size the tube since the invention provides improved type tracheal tubes in which proximal end portions may be cut away to size the tube. Also with these improved tubes, compound bends and directions are easily accomplished. In addition, the new tubes lock into the set shape so that there is no side thrust as can be caused by a resilient bellows type connector such as disclosed in U.S. Pat. No. 3,388,705. Hence, the patients, the anesthetists, the surgeon and the hospitals all benefit from the unique improvements provided by the invention.